1. Field of the Invention
This invention relates to the art of semiconductor device manufacturing, and more specifically, to the production of negative temperature coefficient (NTC) and positive temperature coefficient (PTC) semiconductor thermoresistors based upon Si and/or Ge for a temperature range of between −50° C. to +500° C.
2. Discussion of the Background Art
Semiconductor NTC thermistors for high temperature measurements are based upon ceramic materials and produced from of a mix of metal oxides such as Mn, Fe, Co, Ni, and Zn. Such thermistors are the main type of high temperature thermistors employed in the industry, and have been for many years. The electroconductivity of these thermistors strongly depends on their composition, doping impurities, condition of high temperature annealing and pressure. This makes electrical performance of these devices (resistivity value and temperature dependence of resistivity) difficult to reproduce with a high accuracy. As a result, ceramic thermistors are not interchangeable, and for high accuracy temperature measurements it is necessary to calibrate them for different temperature ranges. This significantly increases the cost of production. In addition, in ceramic thermistors a resistivity change with temperature is not very steep. As a result, the sensitivity of these thermistors is not very high. Their maximum working temperature range does not exceed 350° C. Thus, low performance, lack of a wide working temperature range, poor interchangeability and high production costs are disadvantages of high temperature ceramic NTC thermistors.